Boiler furnace



March 13, 1934.

c. E. LUCKE 1,950,454

BOILER FURNACE Filed June 16. 1931 Fig-1 2 Sheets-Sheet l INVENTOR @5244& M w/wq ATTORNEYS March 13, 1934. Q LUCKE Q 1,950,454

BOILER FURNACE Filed June 16. 1931 2 Sheets-Sheet 2 INVENTOR PatentedMar. 13, 1934 BOILER FURNACE Charles E. Lucke, New York, N. Y., assignorto Fuller Lehigh Company, Fullerton, Pa., a corporation of DelawareApplication June 16, 1931, Serial No. 544,833

1 Claim.

This invention relates to a furnace that is useful in connection withburning gaseous or powdered fuel or fuel in suspension. The invention isespecially applicable to furnaces for steam boilers, but it is notrestricted to this particular use.

By this invention fuel can be partially burned in the lower portion ofthe furnace and additional air admitted further along in the products ofcombustion to complete the burning of the fuel. The air is admitted at avery large number of points in the gaseous stream in proportion to thecross sectional area of the stream.

The invention will be understood from the description in connection withthe accompanying drawings, in which Fig. 1 is a vertical section throughan illustrative embodiment of the invention; Fig. 2 is a section alongthe line 2-2 of Fig. 1; and Fig. 3 is a section along the line 3-3 ofFig. 2.

In the drawings reference character 1 indicates a furnace that isprovided with one or more burners at the lower portion thereof. Fuel,such as gas, oil or powdered fuel may be introduced through the pipe 2and combustion air through the pipe 3 of the burners in the usual waywith insufiicient air to complete the combustion of the fuel.

A boiler of the Babcock & Wilcox type may be located above the furnace 1with the usual bank of inclined tubes 4 connected to uptake headers 5and downtake headers 6 which are in turn connected to the steam andwater drum 7 of the boiler by the tubes 8 and nipples 9, respectively,with bafiies 10 directing the products of combustion from the furnaceacross the tubes 4 in a plurality of passes to the outlet 11, all in thewellknown way.

Rows of inclined tubes 12 extend across the furnace 1 between the fuelburners and the bank of tubes 4, these tubes 12 being preferablyarranged in pairs and the pairs being stepped in the general directionof the flow of products of combustion. The lower ends of the tubes 12are connected to a V-shaped header 13 and the upper ends thereof areconnected to a V-shaped header 14, the headers 13 and 14 being locatedoutside the furnace walls.

A downtake pipe 15 extends from the water space of the steam and waterdrum '7 to the lower portion or point of the header 13, and uptake pipes16 extend from the upper ends of the header 14 to the steam space of thesteam and water drum, thus providing circulation through the tubes 12.Water circulation through the tubes 12 may, however, be provided inother ways or from other sources. 7

Air pipes or conduits 17 extend across the furnace 1 between the burnersand the bank of tubes 4. These air conduits 17 extend from an air box 18to which a supply of air, which may be preheated, is introduced throughthe inlet 19, through a wall of the furnace and into the opposite wallof the furnace where the ends are closed, as indicated at 20. Theseconduits 17 may be made of refractory material and when they are notmechanically strong enough to avoid the danger of sagging down orbreaking due to their own weight, they may rest upon the pairs of watertubes 12 to support them and also to aid in keeping them cool. A seriesof holes or perforations 21 is provided on each side of each of theconduits 1'7, the series of holes in the respective conduits beingpreferably staggered on opposite sides of the conduits, so that the airescaping from these conduits will be intimately mingled with the risingcombustion products or fuel.

The conduits 17 are preferably inclined to the horizontal and arearranged in a stepped relation with respect to the flow of fuel so thatgreater w areas are provided through which the products of partialcombustion from the lower part of the furnace pass as they are beingmixed with the fresh air from the conduits 17. Two sets of approximatelyhorizontally disposed jets of hot air are thus projected into dividedstreams of hot gases as they pass between the conduits 17. By thisarrangement the flow resistance of the products of combustion isdecreased or a larger number of air conduits are provided per unit ofwidth of gas conduit without increasing the flow resistance of theproducts of combustion.

The operation is as follows: Fuel is introduced into the lower portionof the furnace with a deflciency of combustion air so that only partialcombustion of the fuel takes place below the tubes 12 and conduits 17,thus preventing the lower portion of the furnace walls from becominginjured, and thereby enabling this portion of the furnace walls to bemade cheaper than would be necessary if the temperatures; wereexcessive. The products of partial combustion pass upwardly between theconduits l7 and are thus divided into streams, and more combustion airfrom the holes 21 in the conduits 1'7 is added and mixed with thenumerous streams of products of partial combustion. The numerous jets ofair escaping from the conduits 17, which extend across the furnace,cause fresh combustion air to be quickly and. thoroughly mingled withthe products of combustion so that rapid combustion takes place in thespace between tubes 12 and the bank of tubes 4, this space being madesufficiently large for this purpose. The holes 21 are so placed that thejets of air from these holes strike the streams of products of partialcombustion at angles so as to facilitate ready and intimate mixing ofthe air and fuel.

By employing this invention fuel in a gaseous form, or solid or liquidparticles of fuel in suspension in a gas can be introduced with verylittle or no air below the conduit 17, so that very little or nocombustion takes place below these conduits, and the air for combustionpurposes can be introduced entirely or substantially entirely throughthe conduits 17, so that all or substantially all of the combustiontakes place at or above the place where the jets of air are introduced.In a similar manner, all of the air for combustion purposes may beintroduced below the conduits 17 with very little if any gas, and all orsubstantially all of the gas for combustion purposes may be introducedthrough the conduits 17 instead of air being introduced through theseconduits, so that all or substantially all of the combustion willlikewise be caused to take place above the conduits 17.

With certain relations of the conduits 17 to each other the jetsescaping from a lower conduit may strike the next upper one therebycausing better mixing of the fuel and air to take place.

I claim:

In a water tube boiler, a furnace, a steam and water drum, twocirculation systems connected to said drum and each having tubesextending across said furnace, one of said circulation systemscomprising tubes arranged in stepped relation in a plane at an acuteangle to the direction of travel of gases in said furnace bothimmediately before they reach said tubes and immediately after theyleave them, and perforated air conduits resting upon said tubes.

CHARLES E. LUCKE.

